(a) Field of the Invention
The present invention relates to a document processing apparatus for storing font data of character and graphic patterns in the form of vectors.
The present invention also relates to a document processing apparatus for storing font data of character and graphic patterns in the form of dots and vectors.
(b) Related Background Art
In a conventional document processing apparatus having vector fonts, document font data to be displayed or printed is generally stored as line-segment data of each character in the form of vectors represented by display start and end positions of the character. Schemes for actually generating line segments of these vector fonts are a scheme using line segments, a scheme for interpolating line segments by using arcs or three-dimensional splines, and a scheme for generating line segments by using B-splines. Of vector fonts, fonts for representing character outlines in the form of vectors are often called outline fonts.
Since vector fonts need not have font data in units of character sizes, they require only a small memory capacity and provide smooth outlines of characters even in an enlargement/reduction mode, as compared with fonts constituted by dot matrices.
When a character or the like constituted by such a vector font is developed into pattern data, some characters are displayed as pattern data extending across a plurality of lines (e.g., an integral, a sigma, or "[""]" of a matrix in mathematical expressions). Vector fonts for these symbols are stored in the form of fonts corresponding to character sizes included in one line as in normal characters. When pattern data extending across a plurality of lines is developed, enlargement or the like is performed in correspondence with the number of lines.
When enlargement is performed across a plurality of lines, the patterns of the characters and symbols become unnatural, thus degrading printing quality and resulting in a time-consuming operation in enlargement of font data. This problem occurs in a case where a character is enlarged in either of the row and column directions.
Of characters whose outlines are constituted by vector fonts, plural vector fonts are synthesized to generate one character pattern such as a logograph designed by an externally input character. When this character font is developed into pattern data, an outline of each font data is formed by a closed loop. In synthesis of a plurality of font data to convert synthesized font data into pattern data, no problem occurs when the synthesized font data is converted into a solid black dot pattern. However, for example, when a dot pattern is converted, its outline (boundary) is left unconcealed.
Of characters constituted by these vector fonts, plural vector fonts are synthesized to generate one character pattern. When this character font is developed into pattern data, the divided font data corresponding to character codes must be read out, and these font data are synthesized. The synthesized font data is then converted into a dot pattern. For this reason, it takes a long period of time to display a character or symbol constituted by plural vector fonts. In addition, when an area inside the outline constituted by the synthesized vector font is painted in black or is hatched or meshed with halftone dots, special processing is required for a boundary of each vector font constituted by a closed loop. That is, after each outline font is synthesized, boundary lines are visible in halftone dot meshing although these boundary lines are invisible in painting in black.
For example, as for such a vector font, one character pattern is divided into upper and lower halves and each vector font is stored in correspondence with a character code. When a corresponding character code is input, plural vector fonts are synthesized to generate one character pattern. However, no conventional apparatus capable of performing the above operations is available. In order to develop this character font into pattern data in practice, connections of the font data pose problems. In particular, when font data represents an outline, each font data is constituted by a closed loop. When a plurality of font data are synthesized and the synthesized font data is converted into pattern data, special processing must be performed for the outline portion of each font data.
In a wordprocessor or the like, character and graphic patterns are often displayed in a development display area on the basis of composition data or the like. In order to produce and display a document within a predetermined frame, a display character font corresponding to an input character code is developed within an area recognized by a format or frame input by an operator, thereby performing a pattern display.
Some wordprocessors can modify display data to display hollow characters, reversed characters, italic characters, and shadowed characters (shadow display).
When a character displayed within the display area is modified into an italic character, the italic character and its display frame are unbalanced. For this reason, the display frame must also be inclined in accordance with an inclination angle of the italic character. Similarly, when a display frame is to be inclined at a predetermined angle and a character displayed within the frame is kept upright, the frame and the character are unbalanced. Therefore, the character is also displayed as an italic character. However, italic display processing of the character must be performed independently of that of the frame representing the display area, resulting in cumbersome operations. At the same time, it is difficult to match the inclination angle of the italic character with that of the display frame representing the display area.
A modification of the frame must be performed by inputting a modification coefficient as a parameter from a keyboard regardless of whether the modified display frame is displayed or not. An unskilled operator cannot appropriately set an optimal parameter, and it is therefore difficult to perform a desired character modification. Modification versatility inherent to vector data cannot be sufficiently utilized in a wordprocessor.
When a pattern having dot and vector fonts and extending across a plurality of lines is to be generated and then operations for simultaneously synthesizing a plurality of dot fonts and plural vector fonts are taken into consideration, these operations cannot be equally managed.